1. Field of the Invention
The present invention relates to wafer processing, and more particularly to improving the wafer processing using site-dependent (S-D) procedures and subsystems.
2. Description of the Related Art
Current manufacturing methodology and factory design used for integrated circuits require many tools located as stand-alone platforms or grouped in general areas, usually separated by 2000 feet or more. Facilities to run these tools must therefore also be widely distributed throughout the factory. Typical functions required by these platforms are substrate coating (Adhesion, BARC, TARC, Resist, Top Coat), bake (post apply bake and post exposure bake) imaging (exposure), metrology (overlay, critical dimension, defect and film thickness), pre and post exposure cleaning using in immersion processing, etch (defining the pattern in the underling thin films) and post etch clean-up (polymer and other byproduct removal). Technologies targeting sub 32 nm gate lengths sub will require many of these operations to be repeated to complete a single active layer of the semiconductor device i.e. double BARC, double or triple patterning, double or triple imaging, etc.
The required gate level defect density for 15 nm gate technology is going to be approximately 0.01/cm2 at 10 nm in size per ITRS 2005 roadmap. Critical dimension control will need to be about 0.6 nm (3 sigma), post etch, for the gate element. No lithographic and etch process tool exists with these performance capabilities.
These advanced technologies will need real time, wafer-to-wafer upstream adjustment of the process to maintain acceptable device results. Defectivity requirements will demand less movement of wafers from tool to tool within the factory as those movements add defects and factory clean room cost.
Platforms in use today function as manufacturing “islands”. This does not afford the best CoO development or allow for optimum process control. No 300 mm track design today can meet 300 wafers per hour throughput as claimed possible by some exposure tool manufacturers.